Fluid samples were obtained in two Deep Sea Drilling Project boreholes, during wireline re-entry logging of Operation DIANAUT in the Atlantic Ocean. Chemical compositions of borehole fluids in Hole 395A suggest the presence of bottom water in the entire borehole, with no evidence of interaction with the borehole wall or of exchange with formation waters. Fluids from Hole 534A show compositional changes relative to seawater, suggesting an input of fluid from the formation into the borehole. The borehole fluid data, in combination with data on the chemistry of the pore fluids of the sediments at this site, suggest the presence of an aquifer at a depth below 700 mbsf, the depth of a blockage of the hole. ¿ American Geophysical Union 1992